Prognostic significance of the radiographic pattern of disease in patients with severe acute respiratory syndrome.

OBJECTIVE: This study was performed to evaluate the prognostic significance of the radiographic pattern of disease in probable cases of severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: A retrospective review of 439 radiographs was performed for 51 patients with a final diagnosis of probable SARS. Forty-nine patients were followed up for a mean interval of 23 days (range, 2-63 days). RESULTS: Abnormal findings on a chest radiograph were noted at presentation in 80.4% (41/51) of patients. Four radiographic patterns were seen: normal (group 1) in 19.6% (10/51), focal opacity (group 2) in 39.2% (20/51), multifocal opacities (group 3) in 27.5% (14/51), and diffuse air-space opacification (group 4) in 13.7% (7/51). Radiographic progression of disease occurred in 38.8% (19/49) of the patients in groups 1-4. There were no deaths in groups 1 and 2. In group 3, one (7.7%) of the 13 patients died. Five (71.4%) of the seven patients in group 4 died. Overall, 12.2% (6/49) of the patients died, all of whom had diffuse air-space opacification on the last chest radiograph. In these patients, medical comorbidity was present in 66.7% (4/6), and the exposure history was known in 83.3% (5/6). Death occurred at a mean interval of 18.2 days (range, 9-36 days) from the initial exposure. CONCLUSION: Patients presenting with normal findings or focal air-space opacity on chest radiographs had a good clinical outcome. Patients with multifocal opacities that progressed to diffuse air-space opacification and patients presenting with diffuse air-space opacification had a high fatality rate, but patients in this group were also older and more likely to have comorbid conditions. Patients with SARS present with recognizable patterns of disease that have prognostic significance.